Search Results (50)

Phosphorus is an important nutrient element in aquatic ecosystems, and its concentration directly affects the growth and ecological functions of submerged plants. However, the physiological and molecular mechanisms of P. wrightii’s response to phosphorus stress remain unknown. This study investigated the effects of different phosphorus concentration treatments on P. wrightii through physiological, RNA-seq, and metabolome analysis methods. The results indicated that phosphorus stress affected plant physiology by reducing chlorophyll content, increasing MDA and H₂O₂ accumulation, and activating the antioxidant enzyme system. Multiple phosphorus transporters (PHT, SPX, and PAP) and the transcription factor PHR1 were identified through RNA-seq and RT-qPCR analysis. The glycerol phospholipids represent a decreasing trend after low or high phosphorus stress. Through the combined analysis of RNA-seq and metabolome analysis, the response differences of 6 DAMs and 19 DEGs to the P. wrightii Glycerolipid metabolism and Glycerophospholipid metabolism pathways under different phosphorus stresses were revealed. Our results provide a scientific basis and guidance for restoring submerged plants in shallow lakes and for preventing and controlling eutrophication. Full article

Aquatic plants may rely on seeds to promote population persistence after severe disturbances, such as droughts. We characterized the seed germination dynamics for three Potamogeton species following seed storage under dry versus submerged conditions. Overall germination levels were highest for P. lucens and, more specifically, were higher after submerged storage (70.4%) than dry storage (56.0%). Overall germination levels were lower for the two other species and displayed a different response to storage conditions; they were higher after dry storage (P. natans: 24.6%; P. pectinatus: 28.1%) than submerged storage (10.8 and 7.1%, respectively). Only P. natans would have likely made a large seed bank contribution as follows: 42.2% of its seeds remained ungerminated and viable after submerged storage, while this figure was 17.4% for seeds that had experienced dry storage. Our results suggest the species differ in their reproductive strategies. Sexual reproduction plays an important role in Potamogeton lucens, adding new individuals to plant populations every year; however, the low viability of the species’ ungerminated seeds suggest its seed bank contribution may be small, rendering it vulnerable to long periods of unfavourable environmental conditions. In contrast, P. natans would likely make a larger seed bank contribution, underscoring the role its seeds may play in population persistence across years. Potamogeton pectinatus may minimally rely on its seeds, which fits with its predominant use of vegetative reproduction in the field. While its seeds might contribute little to population persistence, they may nonetheless promote genetic variability among populations. Full article

Aquatic plants, as sedentary lifestyle organisms that accumulate chemical substances from their surroundings, can serve as valuable indicators of long-term anthropogenic pressure. In Poland, water monitoring is limited both spatially and temporally, which hampers a comprehensive assessment of water quality. Since the implementation of the Water Framework Directive (WFD), biotic elements, including macrophytes, have played an increasingly important role in water monitoring. Moreover, running waters, due to their dynamic nature, are susceptible to episodic pollution inputs that may be difficult to detect during isolated, point-in-time sampling campaigns. The analysis of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope signatures in macrophytes enables the identification of elemental sources, including potential pollutants. Research conducted between 2008 and 2011 encompassed 38 sites along 15 rivers and 108 sites across 21 lakes in northern Poland. This study focused on the isotope signatures of three pondweed species: Stuckenia pectinata, Potamogeton perfoliatus, and Potamogeton crispus. The results revealed statistically significant differences in the δ¹³C and δ¹⁵N values of plant organic matter between river and lake environments. Higher δ¹⁵N values were observed in rivers, whereas higher δ¹³C values were recorded in lakes. Spearman correlation analysis showed a negative relationship between δ¹³C and δ¹⁵N, as well as correlations between δ¹⁵N and the concentrations of Ca²⁺ and HCO₃⁻. A positive correlation was also found between δ¹³C and dissolved oxygen levels. These findings confirm the utility of δ¹³C and, in particular, δ¹⁵N as indicators of anthropogenic eutrophication, including potentially domestic sewage input and its impact on aquatic ecosystems. Full article

Potamogeton crispus (P. crispus), with strong nitrogen uptake capacity, plays an important ecological role during winter and early spring when most aquatic plants are inactive. Its presence can also influence microbial denitrification in sediments by regulating oxygen levels and organic carbon availability. In this study, an indoor hydroponic simulation system was used to systematically evaluate the effects of P. crispus under different nitrogen-loading conditions on nitrogen removal from water, changes in sediment carbon and nitrogen fractions, microbial community structure, and greenhouse gas fluxes. The results showed that P. crispus effectively removed TN, NH₄⁺-N, NO₃⁻-N, and NO₂⁻-N, maintaining strong denitrification capacity even under high-nitrogen loading. Under all nitrogen conditions, TN removal exceeded 80%, while NH₄⁺-N and NO₃⁻-N removal efficiencies surpassed 90%, with effective suppression of NO₂⁻-N accumulation. Rhizosphere-mediated regulation by P. crispus enhanced the transformation and stabilization of DOC and NO₃⁻-N in sediments, while also mitigating nitrogen-induced disturbances to carbon–nitrogen balance. The plant also exhibited strong CO₂ uptake capacity, low CH₄ emissions with a slight increase under higher nitrogen loading, and N₂O fluxes that were significantly affected by nitrogen levels—showing negative values under low nitrogen and sharp increases under high-nitrogen conditions. Correlation analyses indicated that CO₂ and N₂O emissions were mainly regulated by microbial taxa involved in carbon and nitrogen transformation, while CH₄ emissions were primarily driven by methanogenic archaea and showed weaker correlations with environmental factors. These findings highlight the importance of water restoration during low-temperature seasons and provide a theoretical basis for integrated wetland management strategies aimed at coordinated pollution reduction and carbon mitigation. Full article

The Tigris-Euphrates basin hosts a diverse assemblage of native aquatic plants vital to the region’s ecological and cultural heritage. However, decades of hydrological alterations, pollution, salinity intrusion, habitat destruction, and climate change have caused significant declines in aquatic plant species diversity. This review compiles historical and contemporary information on key native aquatic plant species, assesses their current conservation status, identifies major threats, and provides recommendations for their protection. Sensitive submerged and floating species, including Vallisneria spiralis, Najas marina, and Potamogeton spp., have been particularly affected, with many now being rare or locally extinct. Although restoration efforts in the Mesopotamian Marshes have partially restored some wetlands, aquatic plant conservation remains largely overlooked. We propose targeted recovery plans, integration of aquatic plants into wetland management, enhancement of water quality measures, and increased cross-border hydrological cooperation. Protecting native aquatic flora is essential for maintaining the ecological integrity and resilience of the Tigris-Euphrates basin. Full article

Under conditions of increasing anthropogenic load, aquatic ecosystems all over the world are undergoing a transformation, expressed in the growth of eutrophication, the overgrowing of water bodies with higher vegetation of macrophytes, cyanobacterial bloom, and the increased concentrations of different pollutants in these objects. In the region of Eastern Siberia that we studied, located in the middle reaches of the Lena River basin, there is the city of Yakutsk—the largest city in the world built in a permafrost region. Within the city and its surroundings, there are many small lakes (less than 1 km² in area) which over the past decades have been subject to varying degrees of pressure associated with human activity (nutrients and organic matter loads, urban landscape transformation). This study is the first to combine the metabolomic profiling of Potamogeton perfoliatus with microalgal bioindication to assess anthropogenic impacts in permafrost urban lakes, providing a novel framework for monitoring ecological resilience in extreme environments. We studied four lakes with varying degrees of anthropogenic pressure. Using a comprehensive assessment of the bioindicator properties of planktonic microalgae and the chemical parameters of water using statistical methods and principal component analysis (PCA), the lakes most susceptible to anthropogenic pressure were identified. Concentrations of pollutant elements in the tissues of the submerged macrophyte aquatic plant Potamogeton perfoliatus L., which inhabits all the lakes we studied, were estimated. Data on the content of pollutant elements in aquatic vegetation and the results of metabolomic analysis made it possible to identify the main sources of anthropogenic impact in the urbanized permafrost area. The pollution of water bodies with some key pollutants leads to Potamogeton perfoliatus’s metabolites decreasing, such as sucrose, monosaccharides (arabinose, mannose, fructose, glucose, galactose), organic acids (glyceric acid, malic acid, erythronic acid, fumaric acid, succinic acid, citric acid), fatty acids (linoleic and linolenic acids), myo-inositol, 4-coumaric acid, caffeic acid, rosmarinic acid, shikimic acid, and catechollactate, caused by pollution which may decrease the photosynthetic activity and worsen the sustainability of water ecosystems. Linkage was established between the accumulation of pollutants in plant tissues, the trophic status of the lake, and the percentage of eutrophic microalgae, which can be used in monitoring the anthropogenic load in the permafrost zone. Knowledge of the composition and concentration of secondary metabolites produced by macrophytes in permafrost lakes can be useful in organizing water resource management in terms of reducing the level of cyanobacterial blooms due to allelochemical compounds secreted by macrophytes. This new work makes possible the evaluation of the permafrost-zone small-lake anthropogenic load in the frame of a changing climate and the growing attention of the industry to Arctic resources. Full article

Urbanization significantly impacts river ecosystems, altering fish community structure and dynamics and posing challenges to the sustainable management of these vital resources. In the heavily urbanized Haihe River in China, understanding the spatial and seasonal variations of fish communities and the environmental factors influencing them is crucial for effective conservation and sustainable management. This study investigated fish communities and environmental variables at ten sites along an urbanization gradient in the upstream reach of the Haihe River over four seasons in 2023. A total of 6710 individual fishes representing 30 species were collected. The results showed that the most urbanized section exhibited higher species diversity but was dominated by tolerant, omnivorous species with similar functional traits, indicating functional homogenization. In contrast, less urbanized sections displayed greater seasonal fluctuations and supported species with specialized traits. Key environmental factors influencing fish community dynamics included nitrogen levels, water temperature, dissolved oxygen, and the abundance of the submerged macrophyte Potamogeton crispus. These factors varied spatially and seasonally, mediating the effects of urbanization on fish communities. The findings highlight the importance of environmental factors in shaping fish community dynamics in urban rivers and underscore the need for integrated management strategies that consider both anthropogenic impacts and natural influences to conserve fish diversity, river maintain ecosystem health and ensure long-term sustainability. Sustainable management practices that balance development with environmental protection are vital for preserving ecological integrity and enhancing the resilience of urban river systems to challenges such as urbanization. Full article

Submerged macrophytes play an important role in maintaining the structure and function of shallow lakes. Under eutrophication, the community of submerged macrophytes shows a shift of growth forms from rosette-like to canopy-forming macrophytes and a further decline due to the increasing shading from epiphyton and phytoplankton. However, at the early phase of eutrophication, the population of submerged macrophytes may increase due to increased nutrient availability, and the responses of submerged macrophytes to eutrophication are expected to be growth-form dependent. To explore the direct effects of nutrient enrichment on the submerged macrophytes of both growth forms, we constructed a mesocosm study with rosette-like macrophytes (Vallisneria denseserrulata and V. spinulosa) and canopy-forming macrophytes (Potamogeton lucens and P. wrightii) under two nutrient levels but maintained low phytoplankton and epiphyton biomass. Nutrient enrichment had a positive effect on the plant size for both macrophyte growth forms under low algal shading. Based on the 21 plant traits determined, the same growth form responded similarly to the increase in nutrient availability with few exceptions. Interestingly, increased nutrient levels induced different allocation strategies between canopy-forming (especially for ‘magnopotamid’) and rosette-like submerged macrophytes. The increased nutrients promoted leaf growth in rosette-like macrophytes and ramet production in canopy-forming macrophytes. These results provide a case study on the direct effects of increased nutrient levels on submerged macrophytes during the early phase of eutrophication in shallow lakes. Full article

Ponds are important habitats for aquatic plants and other biota, particularly in regions where the quality of aquatic ecosystems is deteriorating or even disappearing. Ponds provide refuge for many species and serve as foraging places for others. The ponds studied are located in the Brdo Estate and are under special protection to maintain their educational and other ecosystem services. This study examined the temporal differences (20 years) of the plant communities in eleven ponds concerning eutrophication and/or other human pressures. Various measurements were taken between the two surveys to improve the quality of inflowing water. The selected ponds’ physical and chemical parameters, water depth, and transparency were measured. According to our results, water transparency and temperature significantly shaped the structure of the plant community and significantly influenced the presence and abundance of aquatic plants. The changes were reflected in the disappearance of four species of the genus Potamogeton, namely P. filiformis, P. lucens, P. pectinatus, and P. trichoides, which were recorded in 2001 but not in 2021. Secondly, the average number of plant species in the ponds has slightly increased in 20 years, mainly due to emergent plants. The construction of wastewater treatment plants in the catchment area prevented the eutrophication processes. Full article

Under the background of global change, the lake water environment is facing a huge threat from eutrophication. The rapid increase in curly-leaf pondweed (Potamogeton crispus L.) in recent years has seriously threatened the ecological balance and the water diversion safety of the eastern route of China’s South-to-North Water Diversion Project. The monitoring and control of curly-leaf pondweed is imperative in shallow lakes of northern China. Unmanned Aerial Vehicles (UAVs) have great potential for monitoring aquatic vegetation. However, merely using satellite remote sensing to detect submerged vegetation is not sufficient, and the monitoring of UAVs on aquatic vegetation is rarely systematically evaluated. In this study, taking Nansi Lake as a case, we employed Red–Green–Blue (RGB) UAV and satellite datasets to evaluate the monitoring of RGB Vegetation Indices (VIs) in pondweed and mapped the dynamic patterns of the pondweed Fractional Vegetation Coverage (FVC) in Nansi Lake. The pondweed FVC values were extracted using the RGB VIs and the machine learning method. The extraction of the UAV RGB images was evaluated by correlations, accuracy assessments and separability. The correlation between VIs and FVC was used to invert the pondweed FVC in Nansi Lake. The RGB VIs were also calculated using Gaofen-2 (GF-2) and were compared with UAV and Sentinel-2 data. Our results showed the following: (1) The RGB UAV could effectively monitor the FVC of pondweed, especially when using Support Vector Machine that (SVM) has a high ability to recognize pondweed in UAV RGB images. Two RGB VIs, RCC and RGRI, appeared best suited for monitoring aquatic plants. The correlations between four RGB VIs based on GF-2, i.e., GCC, BRI, VDVI, and RGBVI and FVC_SVM calculated by the UAV (p < 0.01) were better than those obtained with other RGB VIs. Thus, the RGB VIs of GF-2 were not as effective as those of the UAV in pondweed monitoring. (2) The binomial estimation model constructed by the Normalized Difference Water Index (NDWI) of Sentinel-2 showed a high accuracy (R² = 0.7505, RMSE = 0.169) for pondweed FVC and can be used for mapping the FVC of pondweed in Nansi Lake. (3) Combined with the Sentinel-2 time-series data, we mapped the dynamic patterns of pondweed FVC in Nansi Lake. It was determined that the flooding of pondweed in Nansi Lake has been alleviated in recent years, but the rapid increase in pondweed in part of Nansi Lake remains a challenging management issue. This study provides practical tools and methodology for the innovative remote sensing monitoring of submerged vegetation. Full article

Elodea nuttallii represents non-native and highly invasive species in Europe that significantly influence freshwater plant communities by decreasing the diversity of native species. This study aimed to determine whether the morphological and anatomical features of Potamogeton gramineus, a native species in Vlasina Lake, differ between sites where it coexists with E. nuttallii and those where E. nuttallii is not present. Environmental variables such as water depth, temperature, pH, conductivity, saturation, and O₂ concentration were included in the analysis. Analyses were conducted on 32 morphological and anatomical features of P. gramineus collected from six sites within Vlasina Lake, comprising three sites where E. nuttallii was present and three sites where it was absent. The datasets containing morphometric and environmental variables underwent analysis using standard univariate techniques (Descriptive, ANOVA), Tukey’s Honest Significant Difference (HSD) test, Student’s t-test, and the Mann–Whitney U test, as well as multivariate statistical methods such as Canonical Discriminant Analysis (CDA). The results show the presence of morphological differentiation among P. gramineus individuals across the analyzed sites. These findings suggest that morphological and anatomical features, such as epidermis, mesophyll, palisade, and aerenchyma tissue thickness in floating leaves, number, length, width, and the surface area of stomata, as well as the width of submersed leaves and stem aerenchyma tissue thickness, effectively differentiate individuals that coexist with E. nuttallii and individuals that growth without its presence. Moreover, they indicate that P. gramineus exhibits a notable ability to modify its morphological traits in response to invasion. Full article

The effects of submerged plant-induced calcium and phosphorus coprecipitation on the phosphorus cycle in aquatic environments and interspecific differences are still unclear. Herein, we selected Ceratophyllum demersum L. and Potamogeton crispus L. to construct a sediment–water-submerged plant system. We examined how phosphorus concentrations in the water, sediment, and plant ash changed over time with different phosphorus and calcium treatments and explored the effects of photosynthesis-induced calcium and phosphorus coprecipitation on water’s phosphorus cycle and variations between different submerged plant species. The main results were as follows: (1) The phosphorus reduction in the P. crispus system was less than that in the C. demersum system. (2) P. crispus had higher total ash phosphorus (TAP) values than C. demersum. (3) The sediment total phosphorus (STP) and its fractions with P. crispus were most affected by phosphorus concentration while those with C. demersum were most affected by time. Overall, the two submerged species exhibited different calcium and phosphorus coprecipitation levels and had distinct effects on the water-to-phosphorus cycle. When submerged plants are introduced to reduce and stabilize the phosphorus levels, plant interspecific differences in their induced calcium and phosphorus coprecipitation on water and phosphorus cycling must be fully assessed. Full article

Aerobic composting is one of the methods for the resource utilization of submerged plant residues. This study investigated the effects of biochar, wetland sediments and microbial agents added individually or combined on the humification process, lignocellulose degradation and microbial communities during Ceratophyllum demersum and Potamogeton wrightii composting. The results showed that the addition of wetland sediment and biochar was found to significantly elevate the composting temperature and humification of compost products. The average content of lignin in wetland sediment and/or biochar treatments was 12.2–13.5%, which was higher than the control group (10.9–11.45%). Compared with the organic matter (19.4%) and total nitrogen concentration (35.3%) of compost treated with complex microbial agent treatments, the homemade microbial agents significantly increased the values by 22.1% and 41.0%, respectively. By comparing the differences in microbial communities among different treatments, the sediments and homemade agents demonstrated greater increases in activity and diversity of lignocellulose degradation-related microbes, especially for Truepera and Actinomarinale. Humus component and temperature were the most critical parameters influencing the changes in the bacterial community. Based on these results, a combination of biochar and homemade agents was a promising additive for an effective composting strategy, and sediment was identified as a potential control of bacterial diversity in wetland plant compost. Full article

The increasing use of herbicides in intelligent agricultural production is driven by the time-consuming nature of manual weeding, as well as its ephemeral effectiveness. However, herbicides like butachlor degrade slowly and can be washed away by rainwater, ultimately flowing into the farm ponds and posing risks to aquatic plants. To identify and recommend superior restoration strategies that effectively address the challenges posed by butachlor, we investigated the impacts of butachlor on the growth and physiology of four common aquatic plants (i.e., Hydrilla verticillata, Ceratophyllum demersum, Potamogeton maackianus, and Myriophyllum aquaticum) and their potential role in mitigating environmental damage by reducing residual herbicide levels. Our findings indicated that M. aquaticum was tolerant to butachlor, exhibiting higher growth rates than other species when exposed to various butachlor concentrations. However, the concentration of butachlor negatively impacted the growth of H. verticillata, C. demersum, and P. maackianus, with higher concentrations leading to more significant inhibitory effects. After a 15-day experimental period, aquatic plants reduced the butachlor residuals in culture mediums across concentrations of 0.5 mg/L, 1 mg/L, and 2 mg/L compared to non-plant controls. Our findings classified P. maackianus as butachlor-sensitive and M. aquaticum as butachlor-tolerant species. This investigation represents novel research aimed at elucidating the contrasting effects of different concentrations of butachlor on four common aquatic species in the agricultural multi-pond system. Full article

In alpine Lake Bohinj, which is an LTER site and a part of the national park, the occurrence and depth distribution of submerged and emerged aquatic macrophytes were analyzed. Nine submerged and one emergent macrophyte taxa were found in the lake: Myriophyllum spicatum, Chara virgata, Chara aspera, Potamogeton lucens, Potamogeton alpinus, Potamogeton crispus, Potamogeton perfoliatus, Potamogeton pusillus, Ranunculus circinatus with the synonym Batrachium foeniculaceum and the emergent species Phragmites australis. The depth of the vegetation zones was measured using a depth meter and their coordinates were recorded using a GNSS antenna with RTK receiver. These data were used along with a DEM of lake depths to accurately map the potential zone of macrophyte growth, which was based on the depths of macrophyte distribution. The potential zone of macrophyte growth consisted of 28 different transects and covered 240.14 ha of the lake. The macrophytes covered 5.55 ha. The most common and abundant species was M. spicatum. A significant difference in macrophyte cover was found between the south and north shores of the lake, with the south shore having more patches with a larger total area. A clear difference in macrophyte cover was also noted between the main inflow and outflow of the lake. The presence of macrophytes and their diversity varied in different parts of the lake due to differences in slope, depth and type of substrates. Full article